Effect of a financial incentive (shopping point) on increasing the number of daily walking steps among community-dwelling adults in Japan: a randomised controlled trial

OBJECTIVE

The aim of this study was to investigate the effect of a financial incentive on the number of daily walking steps among community-dwelling adults in Japan.

STUDY DESIGN

Two-arm, parallel-group randomised controlled trial.

SETTING/PARTICIPANTS

We recruited physically inactive community-dwelling adults from Sendai city, Japan. Eligible participants were randomly allocated to an intervention or a wait list control group. Pedometers were used to assess the mean number of daily steps in three periods: baseline (weeks 1-3), intervention (weeks 4-6) and follow-up (weeks 7-9).

INTERVENTION

The intervention group was offered a financial incentive (shopping points) to meet the target number of increased daily steps in the intervention period.

MAIN OUTCOME MEASURES

The primary outcome was an increase in the mean number of daily steps in the intervention and follow-up periods compared with baseline.

RESULTS

Seventy-two participants (69.4% women; mean age, 61.2±16.2 years; mean number of daily steps at baseline, 6364±2804) were randomised to the intervention (n=36) and control groups (n=36). During the intervention period, the increase in mean daily steps was significantly higher in the intervention group (1650, 95% CI=1182 to 2119) than in the control group (514, 95% CI=136 to 891; p<0.001). However, the difference between groups was not significant at follow-up after the incentives were removed (p=0.311). In addition, compared with controls, a significantly higher proportion of participants in the intervention group showed an increase in mean daily steps of ≥1000 (69.4% vs 30.6%, respectively; OR=5.17, 95% CI=1.89 to 14.08). There were no adverse effects from the intervention.

CONCLUSIONS

The present results suggest that financial incentives are effective in promoting short-term increases in physical activity.

TRIAL REGISTRATION NUMBER

UMIN000033276.

Randomised controlled trial of a financial incentive for increasing the number of daily walking steps: study protocol

INTRODUCTION

Physical activity is one of the major modifiable factors for promotion of public health. Although it has been reported that financial incentives would be effective for promoting health behaviours such as smoking cessation or attendance for cancer screening, few randomised controlled trials (RCTs) have examined the effect of financial incentives for increasing the number of daily steps among individuals in a community setting. The aim of this study is to investigate the effects of financial incentives for increasing the number of daily steps among community-dwelling adults in Japan.

METHODS AND ANALYSIS

This study will be a two-arm, parallel-group RCT. We will recruit community-dwelling adults who are physically inactive in a suburban area (Nakayama) of Sendai city, Japan, using leaflets and posters. Participants that meet the inclusion criteria will be randomly allocated to an intervention group or a waitlist control group. The intervention group will be offered a financial incentive (a chance to get shopping points) if participants increase their daily steps from their baseline. The primary outcome will be the average increase in the number of daily steps (at 4-6 weeks and 7-9 weeks) relative to the average number of daily steps at the baseline (1-3 weeks). For the sample size calculation, we assumed that the difference of primary outcome would be 1302 steps.

ETHICS AND DISSEMINATION

This study has been ethically approved by the research ethics committee of Tohoku University Graduate School of Medicine, Japan (No. 2018-1-171). The results will be submitted and published in a peer-reviewed scientific journal.

TRIAL REGISTRATION NUMBER

UMIN000033276; Pre-results.

Joint impact of seven risk factors on incident dementia in elderly Japanese: the Ohsaki Cohort 2006 Study

BACKGROUND

This cohort study estimated the population attributable fraction (PAF) of seven combined major risk factors for incident dementia.

METHODS

We conducted a cohort study of 8563 community-dwelling individuals aged ≥ 65 years. In a baseline survey (2006), we collected data on major seven risk factors: diabetes mellitus, hypertension, obesity, physical inactivity, severe psychological distress, smoking, and low educational attainment. The total number of risk factors was applied as an exposure variable. Subjects were categorized into four groups according to the total number of risk factors they possessed (0, 1, 2, ≥ 3 risk factors). Data on incident dementia were retrieved from the public Long-term Care Insurance database. Hazard ratios (HRs) and 95% confidence interval (95% CI) were estimated using the Cox proportional regression model. We also calculated the PAF using HRs and the prevalences in our cohort data.

RESULTS

The number of cases of incident dementia was 577 (6.7%). A dose-response relationship between the total number of risk factors and incident dementia was observed; in comparison with no risk factors (reference), the age- and sex-adjusted HRs (95% CIs) were 1.25 (0.92-1.70) for one risk factor, 1.59 (1.18-2.15) for two, and 2.21 (1.62-3.01) for three or more (P trend < 0.001). If subjects had adhered to none of the risk factors, the PAF would have been 32.2%. If subjects had improved toward one better category, the PAF would have been 23.0%.

CONCLUSION

Our findings suggest that reducing the combined number of risk factors would contribute significantly to reducing the incidence of dementia.

Confirmation of domoic acid production of Pseudo-nitzschia multiseries isolated from Ofunato Bay, Japan

Production of domoic acid (DA), the responsible toxin for amnesic shellfish poisoning, was examined for 44 strains of Pseudo-nitzschia spp. isolated from Ofunato Bay, Japan. Only one strain which was identified as Pseudo-nitzschia multiseries produced DA in a level comparable to Canadian strains. No significant DA was detected in the rest of the strains, indicating that toxic P. multiseries does not bloom in a high density in the bay.

Occurrence of okadaic acid-producing Prorocentrum lima on the Sanriku coast, northern Japan

Prorocentrum lima was found to be distributed on the surface of the algae, Sargassum confusum and Carpopeltis flabellata collected at the Sanriku coast, northern Japan. Chemical analysis of cultured cells revealed that Sanriku strains of P. lima produce okadaic acid, a toxin responsible for diarrhetic shellfish poisoning. The Sanriku strain grew well in T1 medium at 15 degrees C at which tropical strains do not grow, indicating that it is a local strain which adapts to cooler environments.

Standardization of HbA1c value and its comparison to immunoassay--two years of experience

In spite of the routine use of hemoglobin Alc (HbAlc) value to guide diabetes therapy, substantial differences have been noted between results obtained by different instruments and laboratories. It was suggested that confusion between the terms used for HbA1c, i.e. between "total HbA1c' which includes labile content, and "stable HbA1c', which does not, may account for some of these inter-instrument and inter-laboratory differences. However, an undesirable difference was found even in measurements of only the stable component of HbAlc using the two most commonly used HPLC analyzers in our country. We found that a two-point calibration using lyophilized hemoglobin at lower and higher ranges was effective in matching up results of HbA1c measurement. This finding was concordant with a report by the Committee of the Japan Diabetes Society and other reports. Two methods of HbA1c immunoassay, one performed with the DCA 2000 automated analyzer and another performed using the Liquitech kit or a general automated analyzer, were evaluated and found to perform as well as HPLC analyzers in all respects except precision. The results derived from immunoassay were in good agreement with the calibrated results by HPLC, with (Liquitech) and without (DCA 2000) conversions.